Pregnancy marks a period of extreme physiological change as the maternal immune, endocrine, and metabolic systems rapidly adapt to sustain the growing fetus. It is conventionally assumed that these pregnancy-induced changes (e.g., elevated lipids, insulin resistance, weight gain) reverse by 6-months postpartum. Yet, evidence suggests that for some women physiological changes persist and may confer long-term risk of chronic diseases such as cardiovascular disease (CVD). We have demonstrated, for example, that inflammatory markers that confer risk for CVD may stay elevated above pre-pregnancy levels beyond 6-months postpartum. Thus, characterizing weight and biological changes across pregnancy-postpartum, predicting the women at risk for adverse cardiometabolic profiles, and identifying modifiable factors that mitigate these profiles offer opportunities to create targeted interventions to prevent future chronic disease. To improve our understanding of the nature of biological changes in the pregnancy-postpartum period that may predict cardiometabolic risk, we propose a cost-efficient longitudinal study extending from the first trimester through 3 years postpartum that capitalizes on the infrastructure of an ongoing pregnancy cohort (R01 HD083369). The parent study, which focuses on maternal prenatal biology as it relates to child health outcomes, is currently recruiting a socioeconomically and racially diverse sample of 290 first trimester pregnant women. Blood, saliva, anthropometry, and psychosocial, lifestyle, and health data are collected across pregnancy in the parent study. We will leverage the existing infrastructure and data collected as part of the parent study and expand that existing framework by (1) assessing additional biomarkers from banked prenatal maternal samples and obtaining new maternal biological samples at 6, 12, and 36 months postpartum; (2) examining how maternal weight, immune, endocrine, and metabolic biomarkers from the first trimester through 12 months postpartum predict subsequent cardiometabolic risk in the mother, and (3) identifying modifiable maternal health behaviors that may mitigate adverse cardiometabolic health outcomes. Our over-arching premise is that the immune, endocrine, metabolic, and weight changes of pregnancy can be long-lasting and contribute to an adverse cardiometabolic profile that increases long-term chronic disease risk. The aims are to: (1) identify maternal weight profiles in the pregnancy-postpartum period that predict adverse cardiometabolic risk profiles three years postpartum; (2) describe immune, endocrine, and metabolic biomarker profiles in the pregnancy- postpartum period, and determine their associations with cardiometabolic risk; and (3) determine how modifiable health behaviors are associated with weight and biomarker changes in the postpartum period and predict cardiometabolic risk. The significance of this project is high given the increasing rates of obesity in pregnant women and the need for targeted, biologically and psychosocially informed treatments to prevent cardiometabolic disease in women.